From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0046AC636CC for ; Mon, 13 Feb 2023 14:57:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230148AbjBMO5V (ORCPT ); Mon, 13 Feb 2023 09:57:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231145AbjBMO5G (ORCPT ); Mon, 13 Feb 2023 09:57:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1B3E1DB97 for ; Mon, 13 Feb 2023 06:56:43 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 645F2B80E62 for ; Mon, 13 Feb 2023 14:56:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9409C433D2; Mon, 13 Feb 2023 14:56:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1676300184; bh=zfY/whVn6HYIuiXAw3hxr53jrQkSstb/81pyrNbv6wY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hTNOmdmMJ54xBcMZBB0qbKyNaTihWoekWoVmCXHkHOGz1N3x1mZnJKyASwX2x22wY xNS5p7ONrE5+CNNk4W26jeS6mH0Iwq5ojSQp2CE7tZaDbaDFRpT7ahyQX4ugBFXuSM N1yxjuZ+zyKjimadVdKC4vnw3KjzUkU9DGm7aJP4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sachin Sant , Nicholas Piggin , Michael Ellerman Subject: [PATCH 6.1 096/114] powerpc/64s/interrupt: Fix interrupt exit race with security mitigation switch Date: Mon, 13 Feb 2023 15:48:51 +0100 Message-Id: <20230213144747.144563374@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230213144742.219399167@linuxfoundation.org> References: <20230213144742.219399167@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nicholas Piggin commit 2ea31e2e62bbc4d11c411eeb36f1b02841dbcab1 upstream. The RFI and STF security mitigation options can flip the interrupt_exit_not_reentrant static branch condition concurrently with the interrupt exit code which tests that branch. Interrupt exit tests this condition to set MSR[EE|RI] for exit, then again in the case a soft-masked interrupt is found pending, to recover the MSR so the interrupt can be replayed before attempting to exit again. If the condition changes between these two tests, the MSR and irq soft-mask state will become corrupted, leading to warnings and possible crashes. For example, if the branch is initially true then false, MSR[EE] will be 0 but PACA_IRQ_HARD_DIS clear and EE may not get enabled, leading to warnings in irq_64.c. Fixes: 13799748b957 ("powerpc/64: use interrupt restart table to speed up return from interrupt") Cc: stable@vger.kernel.org # v5.14+ Reported-by: Sachin Sant Tested-by: Sachin Sant Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20230206042240.92103-1-npiggin@gmail.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/kernel/interrupt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -50,16 +50,18 @@ static inline bool exit_must_hard_disabl */ static notrace __always_inline bool prep_irq_for_enabled_exit(bool restartable) { + bool must_hard_disable = (exit_must_hard_disable() || !restartable); + /* This must be done with RI=1 because tracing may touch vmaps */ trace_hardirqs_on(); - if (exit_must_hard_disable() || !restartable) + if (must_hard_disable) __hard_EE_RI_disable(); #ifdef CONFIG_PPC64 /* This pattern matches prep_irq_for_idle */ if (unlikely(lazy_irq_pending_nocheck())) { - if (exit_must_hard_disable() || !restartable) { + if (must_hard_disable) { local_paca->irq_happened |= PACA_IRQ_HARD_DIS; __hard_RI_enable(); }